src/journal-remote/microhttpd-util.c

   1 /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
   2
   3 /***
   4   This file is part of systemd.
   5
   6   Copyright 2012 Lennart Poettering
   7   Copyright 2012 Zbigniew Jędrzejewski-Szmek
   8
   9   systemd is free software; you can redistribute it and/or modify it
  10   under the terms of the GNU Lesser General Public License as published by
  11   the Free Software Foundation; either version 2.1 of the License, or
  12   (at your option) any later version.
  13
  14   systemd is distributed in the hope that it will be useful, but
  15   WITHOUT ANY WARRANTY; without even the implied warranty of
  16   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  17   Lesser General Public License for more details.
  18
  19   You should have received a copy of the GNU Lesser General Public License
  20   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  21 ***/
  22
  23 #include <stddef.h>
  24 #include <stdio.h>
  25 #include <string.h>
  26
  27 #include "microhttpd-util.h"
  28 #include "log.h"
  29 #include "macro.h"
  30 #include "util.h"
  31 #include "strv.h"
  32
  33 #ifdef HAVE_GNUTLS
  34 #include <gnutls/gnutls.h>
  35 #include <gnutls/x509.h>
  36 #endif
  37
  38 void microhttpd_logger(void *arg, const char *fmt, va_list ap) {
  39         char *f;
  40
  41         f = strappenda("microhttpd: ", fmt);
  42
  43         DISABLE_WARNING_FORMAT_NONLITERAL;
  44         log_internalv(LOG_INFO, 0, NULL, 0, NULL, f, ap);
  45         REENABLE_WARNING;
  46 }
  47
  48
  49 static int mhd_respond_internal(struct MHD_Connection *connection,
  50                                 enum MHD_RequestTerminationCode code,
  51                                 char *buffer,
  52                                 size_t size,
  53                                 enum MHD_ResponseMemoryMode mode) {
  54         struct MHD_Response *response;
  55         int r;
  56
  57         assert(connection);
  58
  59         response = MHD_create_response_from_buffer(size, buffer, mode);
  60         if (!response)
  61                 return MHD_NO;
  62
  63         log_debug("Queing response %u: %s", code, buffer);
  64         MHD_add_response_header(response, "Content-Type", "text/plain");
  65         r = MHD_queue_response(connection, code, response);
  66         MHD_destroy_response(response);
  67
  68         return r;
  69 }
  70
  71 int mhd_respond(struct MHD_Connection *connection,
  72                 enum MHD_RequestTerminationCode code,
  73                 const char *message) {
  74
  75         return mhd_respond_internal(connection, code,
  76                                     (char*) message, strlen(message),
  77                                     MHD_RESPMEM_PERSISTENT);
  78 }
  79
  80 int mhd_respond_oom(struct MHD_Connection *connection) {
  81         return mhd_respond(connection, MHD_HTTP_SERVICE_UNAVAILABLE,  "Out of memory.\n");
  82 }
  83
  84 int mhd_respondf(struct MHD_Connection *connection,
  85                  enum MHD_RequestTerminationCode code,
  86                  const char *format, ...) {
  87
  88         char *m;
  89         int r;
  90         va_list ap;
  91
  92         assert(connection);
  93         assert(format);
  94
  95         va_start(ap, format);
  96         r = vasprintf(&m, format, ap);
  97         va_end(ap);
  98
  99         if (r < 0)
 100                 return respond_oom(connection);
 101
 102         return mhd_respond_internal(connection, code, m, r, MHD_RESPMEM_MUST_FREE);
 103 }
 104
 105 #ifdef HAVE_GNUTLS
 106
 107 static struct {
 108         const char *const names[4];
 109         int level;
 110         bool enabled;
 111 } gnutls_log_map[] = {
 112         { {"0"},                  LOG_DEBUG },
 113         { {"1", "audit"},         LOG_WARNING, true}, /* gnutls session audit */
 114         { {"2", "assert"},        LOG_DEBUG },        /* gnutls assert log */
 115         { {"3", "hsk", "ext"},    LOG_DEBUG },        /* gnutls handshake log */
 116         { {"4", "rec"},           LOG_DEBUG },        /* gnutls record log */
 117         { {"5", "dtls"},          LOG_DEBUG },        /* gnutls DTLS log */
 118         { {"6", "buf"},           LOG_DEBUG },
 119         { {"7", "write", "read"}, LOG_DEBUG },
 120         { {"8"},                  LOG_DEBUG },
 121         { {"9", "enc", "int"},    LOG_DEBUG },
 122 };
 123
 124 void log_func_gnutls(int level, const char *message) {
 125         assert_se(message);
 126
 127         if (0 <= level && level < (int) ELEMENTSOF(gnutls_log_map)) {
 128                 if (gnutls_log_map[level].enabled)
 129                         log_internal(gnutls_log_map[level].level, 0, NULL, 0, NULL, "gnutls %d/%s: %s", level, gnutls_log_map[level].names[1], message);
 130         } else {
 131                 log_debug("Received GNUTLS message with unknown level %d.", level);
 132                 log_internal(LOG_DEBUG, 0, NULL, 0, NULL, "gnutls: %s", message);
 133         }
 134 }
 135
 136 int log_enable_gnutls_category(const char *cat) {
 137         unsigned i;
 138
 139         if (streq(cat, "all")) {
 140                 for (i = 0; i < ELEMENTSOF(gnutls_log_map); i++)
 141                         gnutls_log_map[i].enabled = true;
 142                 log_reset_gnutls_level();
 143                 return 0;
 144         } else
 145                 for (i = 0; i < ELEMENTSOF(gnutls_log_map); i++)
 146                         if (strv_contains((char**)gnutls_log_map[i].names, cat)) {
 147                                 gnutls_log_map[i].enabled = true;
 148                                 log_reset_gnutls_level();
 149                                 return 0;
 150                         }
 151         log_error("No such log category: %s", cat);
 152         return -EINVAL;
 153 }
 154
 155 void log_reset_gnutls_level(void) {
 156         int i;
 157
 158         for (i = ELEMENTSOF(gnutls_log_map) - 1; i >= 0; i--)
 159                 if (gnutls_log_map[i].enabled) {
 160                         log_debug("Setting gnutls log level to %d", i);
 161                         gnutls_global_set_log_level(i);
 162                         break;
 163                 }
 164 }
 165
 166 static int verify_cert_authorized(gnutls_session_t session) {
 167         unsigned status;
 168         gnutls_certificate_type_t type;
 169         gnutls_datum_t out;
 170         int r;
 171
 172         r = gnutls_certificate_verify_peers2(session, &status);
 173         if (r < 0)
 174                 return log_error_errno(r, "gnutls_certificate_verify_peers2 failed: %m");
 175
 176         type = gnutls_certificate_type_get(session);
 177         r = gnutls_certificate_verification_status_print(status, type, &out, 0);
 178         if (r < 0)
 179                 return log_error_errno(r, "gnutls_certificate_verification_status_print failed: %m");
 180
 181         log_info("Certificate status: %s", out.data);
 182
 183         return status == 0 ? 0 : -EPERM;
 184 }
 185
 186 static int get_client_cert(gnutls_session_t session, gnutls_x509_crt_t *client_cert) {
 187         const gnutls_datum_t *pcert;
 188         unsigned listsize;
 189         gnutls_x509_crt_t cert;
 190         int r;
 191
 192         assert(session);
 193         assert(client_cert);
 194
 195         pcert = gnutls_certificate_get_peers(session, &listsize);
 196         if (!pcert || !listsize) {
 197                 log_error("Failed to retrieve certificate chain");
 198                 return -EINVAL;
 199         }
 200
 201         r = gnutls_x509_crt_init(&cert);
 202         if (r < 0) {
 203                 log_error("Failed to initialize client certificate");
 204                 return r;
 205         }
 206
 207         /* Note that by passing values between 0 and listsize here, you
 208            can get access to the CA's certs */
 209         r = gnutls_x509_crt_import(cert, &pcert[0], GNUTLS_X509_FMT_DER);
 210         if (r < 0) {
 211                 log_error("Failed to import client certificate");
 212                 gnutls_x509_crt_deinit(cert);
 213                 return r;
 214         }
 215
 216         *client_cert = cert;
 217         return 0;
 218 }
 219
 220 static int get_auth_dn(gnutls_x509_crt_t client_cert, char **buf) {
 221         size_t len = 0;
 222         int r;
 223
 224         assert(buf);
 225         assert(*buf == NULL);
 226
 227         r = gnutls_x509_crt_get_dn(client_cert, NULL, &len);
 228         if (r != GNUTLS_E_SHORT_MEMORY_BUFFER) {
 229                 log_error("gnutls_x509_crt_get_dn failed");
 230                 return r;
 231         }
 232
 233         *buf = malloc(len);
 234         if (!*buf)
 235                 return log_oom();
 236
 237         gnutls_x509_crt_get_dn(client_cert, *buf, &len);
 238         return 0;
 239 }
 240
 241 int check_permissions(struct MHD_Connection *connection, int *code, char **hostname) {
 242         const union MHD_ConnectionInfo *ci;
 243         gnutls_session_t session;
 244         gnutls_x509_crt_t client_cert;
 245         _cleanup_free_ char *buf = NULL;
 246         int r;
 247
 248         assert(connection);
 249         assert(code);
 250
 251         *code = 0;
 252
 253         ci = MHD_get_connection_info(connection,
 254                                      MHD_CONNECTION_INFO_GNUTLS_SESSION);
 255         if (!ci) {
 256                 log_error("MHD_get_connection_info failed: session is unencrypted");
 257                 *code = mhd_respond(connection, MHD_HTTP_FORBIDDEN,
 258                                     "Encrypted connection is required");
 259                 return -EPERM;
 260         }
 261         session = ci->tls_session;
 262         assert(session);
 263
 264         r = get_client_cert(session, &client_cert);
 265         if (r < 0) {
 266                 *code = mhd_respond(connection, MHD_HTTP_UNAUTHORIZED,
 267                                     "Authorization through certificate is required");
 268                 return -EPERM;
 269         }
 270
 271         r = get_auth_dn(client_cert, &buf);
 272         if (r < 0) {
 273                 *code = mhd_respond(connection, MHD_HTTP_UNAUTHORIZED,
 274                                     "Failed to determine distinguished name from certificate");
 275                 return -EPERM;
 276         }
 277
 278         log_info("Connection from %s", buf);
 279
 280         if (hostname) {
 281                 *hostname = buf;
 282                 buf = NULL;
 283         }
 284
 285         r = verify_cert_authorized(session);
 286         if (r < 0) {
 287                 log_warning("Client is not authorized");
 288                 *code = mhd_respond(connection, MHD_HTTP_UNAUTHORIZED,
 289                                     "Client certificate not signed by recognized authority");
 290         }
 291         return r;
 292 }
 293
 294 #else
 295 int check_permissions(struct MHD_Connection *connection, int *code, char **hostname) {
 296         return -EPERM;
 297 }
 298 #endif